This three part series is the OVA to CLAMP's original series Magic Knight Rayearth. The alternate world of Cephiro is crossing over into Earth, causing a number of huge earthquakes. Three high school girls must become the Magic Knights to save their world from destruction.

Hikaru Shido, Umi Ryuzaki, and Fu Ho-oji are three ordinary Japanese schoolgirls who suddenly find themselves transported to Cephiro, a world of magic and monsters in another dimension. Clef, a very youthful looking ancient wizard, tells them that they have been summoned by the guardian of Cephiro, Princess Emeraude. The princess is a "pillar" of Cephiro, the link that holds the magic kingdom together, but she has been kidnapped by the evil High Priest Zagato. In order to save this fragile world, the three girls must literally win their spurs and become Magic Knights, for only the combined powers of the Knights can hope to challenge Zagato and save the world. Clef helps them from time to time, and they have another friend, the rabbit-like Mokona, whose cuddly exterior hides many secrets. Nothing else is quite as it seems either; the sorcerer is in love with the princess, and each of the girls has her own secret strengths and weaknesses. If they are ever to see Tokyo again, they must work together to save Cephiro.

In the second season, the three girls are once again summoned to Cephiro, once again on the brink of oblivion. With Emeraude absent, the three kingdoms of Autozam, Farhen, and Cizeta begin an invasion of Cephiro to overthrow the pillar system. They must also contend with a girl called Nova, who seems to be Hikaru's nemesis and attacks everything she loves.

The three-part 1997 video series keeps the same basic premise but changes the story. To reflect the change, the title became simply Rayearth. Cephiro is slowly materializing in Tokyo and the meeting of two dimensions is causing huge earthquakes on Earth. To avert the impending disaster, Guru Clef and Lantis must find the Magic Knights whose powers can put things right. High school girl Hikaru is waiting for her friends Umi and Fuu under a cherry tree with supposed magic connections when there's another strong quake, and a strangely cute rabbit-like creature, Mokona, falls out. As Hikaru chases the white rabbit and her friends follow, they are all whisked to the Tokyo Tower where they learn that they must summon the Mashin Gods, powerful sentient fighting machines, and use their powers to defeat the sorcerer Eagle Vision and his Mashin if both worlds are to be saved.

Based on a manga in Nakayoshi that combined elements of girls' manga with boys' action-adventure, this magical romance was a huge hit for its creators, manga collective CLAMP, whose work has not always been served well on video (see RG Veda) and had considerable success in the U.S. The three heroines, linked specifically with the elements of fire, water, and air, are more "magical" in origin than anything on Cephiro, where many people and places are named for popular Japanese cars. There are references not only to anime tropes, such as destined heroes who alone can control powerful armor, and popular locations, like the Tokyo Tower that features in numerous shows, but also to Western classics-as in Alice in Wonderland and CLAMP's earlier Miyuki-chan in Wonderland, the girls are guided by a white rabbit.